IR spectroscopy of organic co-crystals of 4-nitrophenol with 2-aminopyridine and 2,6-diaminopyridine

Abstract

IR spectra of co-crystals based on 4-nitrophenol with derivatives of aminopyridines are studied within the range of 450–4500 cm^–1. As samples, 2-aminopyridine–4-nitrophenol and 2,6-diaminopyridine–4-nitrophenol are chosen. The samples are prepared by two methods, i.e., by pressing of potassium bromide pellets and by coating of fluorite with a mixture of the sample with vaseline oil. Comparative analysis shows that the spectra of co-crystals differ from the spectra of mixtures of their components. It is found that some vibrations in the spectra correspond to vibrations of aminogroups probably involved in bonding between components in co-crystals, which confirms the formation of co-crystals.